Unison general secretary Dave Prentis (pictured) admitted the EU was not perfect, but said his members would be better off inGetty

The campaign to keep the UK inside the EU has been a given a considerable boost after Britain's largest public service trade union threw its support behind a 'remain' vote. Unison, which has around 1.3 million members, made the announcement after a meeting of its ruling body on 13 April.

Sources close to the union told IBTimes UK that the National Executive Council (NEC) "overwhelmingly" backed the decision to campaign against a Brexit at the 23 June ballot. A source estimated just three NEC members voted against the move, two others abstained and more than 50 representatives backed the decision.

Unison said almost four in five (78%) of the union's health, local government, education, energy and police branches wanted the union to take a stance in the EU referendum. Of these, 95% wanted Unison to campaign for the UK to stay in the 28-nation-bloc.

"Europe isn't perfect, but on balance staying in the EU has so much more to offer nurses, teaching assistants, town hall staff and other public servants than an uncertain future where the UK goes it alone," said Dave Prentis, the general secretary of Unison.

"Brexit fears have just seen the UK's growth forecast downgraded. NHS, local government, school and police employees bore the brunt of the last economic downturn and are still paying the price.

"The last thing anyone wants is another recession where jobs, living standards and public services are back on the line.

"Without the laws that began life in Europe, most people at work in the UK would be getting a very rough deal. If the June vote is to leave the EU, it would then be up to the government which laws stayed and which laws went. Unscrupulous employers would have a field day."

EU referendum: This is what you really need to know about the Brexit voteIBTimes UK

The Trades Union Congress (TUC), Unite, the Transport Salaried Staff Association (TSSA) and the GMB have already unveiled their support for a 'remain' vote at the referendum. However, rail unions the RMT and Aslef are backing a 'leave' vote alongside the Bakers, Food and Allied Workers Union (BFAWU).

Mick Cash, the general secretary of the 80,000-strong RMT, said: "It would be frankly ludicrous for a union like ours to support staying in a bosses club that seeks to ban the public ownership of our railways, attacks the shipping and offshore sectors and embraces the privatisation of the NHS and other essential services that our members depend on."